Inpex Australia president director Seiya Ito said the first LNG cargo from Ichthys was a historic moment for the company, Japan and Australia.

"Ichthys is an iconic project for Australia,” he said.

The milestone comes about two years after the original production target and at a $US6 billion higher cost than when the project was approved in early 2012.

Production starts at the Ichthys Explorer off the Kimberley coast that takes raw gas from subsea wells and sends condensate to the nearby Ichthys Venturer — a floating production, storage and offloading facility.

The first condensate shipment left in early October.

Gas is sent to Darwin through an 890km pipeline, where the LNG is produced. LPG shipments from Darwin are expected to start later this year.

The Ichthys project is expected to operate for 40 years producing 8.9 million tonnes of LNG, 1.6 million tonnes of LPG and 100,000 barrels of condensate a year.

The shipment leaves Shell’s Prelude floating LNG vessel as the last project from the Australian LNG boom to start production.

In July Shell chief executive Ben van Beurden said Prelude was on track to start production this year “based on our current commissioning schedule”.